For me, the biggest issue with the 300 or the 6.8 is the ammo cost. The ammo is out there. I think all three will do well for a while. The 300 is alot like the 7/62 x 39, but I would say that round is superb if someone made an AK worth a damn! AR's won't feed it, so now we have 300 Blackout.
If you were going to shoot pigs silenced, the 300 would really show it came to play!